Some basis:
SSSP: potential for QE

We use the QE/6.7-gcc-5.4.0-MPI on TH-2 by “module load Quantum_Espresso/6.7-gcc-5.4.0-MPI”

Besides, the bash file we use is ‘qe.sh’

#!/bin/bash
export PATH=/BIGDATA1/app/Quantum_Espresso/6.7-gcc-5.4.0/bin/:$PATH
yhrun -N $SLURM_NNODES -n $SLURM_NTASKS $1 < h2.relax.in >& h2.relax.out

We start from the H2 to obtain the equilibrium bond length.

&control
    calculation = 'relax'
    prefix = 'h2'
    pseudo_dir = '/BIGDATA1/ac_iphy_jrsun_1/soft/QE/SSSP'
/
&system
    ibrav=1, celldm(1) =20, 
    nat=2, ntyp=1,
    ecutwfc=30.0
/
&electrons
    conv_thr=1e-8
/
&ions
    ion_dynamics='bfgs'
/
ATOMIC_SPECIES
 H  1.00784  H.pbe-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS (angstrom)
 H 0.00 0.00 0.00
 H 1.00 0.00 0.00
K_POINTS (automatic)
  1 1 1 0 0 0

Some note: (more detials can be found here)
‘ibrav =1’ means that the Bravais-lattice is simple cubic with basis of $v_{1}=(a,0,0), v_{2}=(0,a,0), v_{3}=(0,0,a)$
‘celldm(1)=20’ means that lattice constant in Bohr. (1Bohr = 0.529 $\overset{\circ}{A}$)
‘nat=2’: number of atoms in the unit cell
‘ntype=2’: number of types of atoms in the unit cell
‘ecutwfc’: kinetic energy cutoff of wavefunction
‘conv_thr’: Convergence threshold for selfconsistency.
‘ion_dynamics’: Specify the type of ionic dynamics;
‘bfgs’: BFGS quasi-newton algorithm,
based on the trust radius procedure,
for structural relaxation.
‘damp’: quick-min Verlet dynamics for structural relaxation

ATOMIC_SPECIES
X Mass_X PseudoPot_X 
Y Mass_Y PseudoPot_Y
ATOMIC_POSITIONS {alat | bohr | crystal | angstrom | crystal_sg}
X 0.0 0.0 0.0 x x x (可以备注x,0 fixed, 1 free)
Y 0.5 0.0 0.0
K_POINTS {tpiba | automatic | crystal | gamma | tpiba_b | crystal_b | tpiba_c | crystal_c}
if (gamma)
    nothing to read
if (automatic)
    nk1, nk2, nk3, k1, k2, k3
if (not automatic)
    nks
    xk_x, xk_y, xk_z, wk
!当ibrav=0时，设置此项
[CELL_PARAMETERS {alat | bohr| angstrom}
v11 v12 v13
v21 v22 v23
v31 v32 v33]

submit: $yhbatch -N 1 -n 1 -p bigdata ./qe.sh pw.x

In h2.relax.out:

Begin final coordinates

ATOMIC_POSITIONS (angstrom)
H             0.1233376814        0.0000000000        0.0000000000
H             0.8766623186        0.0000000000        0.0000000000
End final coordinates

Then we get the optimized hydrogen bond length.